How to mount disk used by ReadyNAS

The following steps are useful if we want to salvage data stored in the drive in ReadyNAS.
I am not sure if the steps below are going to work on other ReadyNAS models, but it works on my ReadyNAS Duo (Sparc CPU).

Basically, what we need is a SATA-to-USB cable (can be bought on the Internet for couple of bucks).
NETGEAR ReadyNAS partitions the drive into 4 partitions.  In my case, it is detected as /dev/sdc:


[root@r3000 media]# fdisk -l /dev/sdc

Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               2     4096001     2048000   83  Linux
/dev/sdc2         4096002     4608001      256000   82  Linux swap / Solaris
/dev/sdc3         4608002  1953092233   974242116    5  Extended
/dev/sdc5         4608003  1953092233   974242115+  8e  Linux LVM
[root@r3000 media]# 

There are couple of issues if we try to mount the partitions directly:

1. ReadyNAS uses non-standard ext3 block-size, which in my case is 16384 bytes (use command "lvsc" to check)
2. The home directory is partitioned as LV group, so conventional mount command is not gonna work

Here's the steps:

• Scan the usb for LVM volumes and identify in the output the volume group name that has your READYNAS volume (mine proved to be c):

# vgscan

[root@r3000 media]# vgscan

  Reading all physical volumes.  This may take a while...

  Found volume group "c" using metadata type lvm2

  Found volume group "vg_r3000" using metadata type lvm2

  Found volume group "VolGroup" using metadata type lvm2

• Activate the group for ReadyNAS (in this case, the group name is "C")

# vgchange -ay c

• Find the logical volume that  (mine proved to be 'c'):

# lvs

• root@r3000:/home/root# lvs
    LV   VG   Attr      LSize   Pool Origin Data%  Move Log Copy%  Convert
    c    c    -wi-ao--- 929.09g   

• To display the logical name of the partition, use command "lvdisplay":

# lvdisplay /dev/c

  --- Logical volume ---

  LV Name                /dev/c/c

  VG Name                c

  LV UUID                7HUOrf-B5bL-ur6r-ULsd-yl4m-gCrA-zQc4s9

  LV Write Access        read/write

  LV Status              available

  # open                 0

  LV Size                929.09 GiB

  Current LE             29731

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:5

We cannot use regular command "mount" to mount the non-standard blocksize ext3 partition.  Fortunately, there is a tool called "fuse-ext3" running in userspace that can help us.  The tool can be downloaded here.

Here's an example how to mount my ReadyNAS's LV volume:

fuse-ext2 -o sync_read,allow_other,rw+ /dev/c/c /media/readynas2

And here is the command to mount the system (root) partition which has the Linux software (I will post later about how to reset root password without resetting the ReadyNAS to factory default etc.)

fuse-ext2 -o sync_read,allow_other,rw+ /dev/c/c /media/readynas2

Note: don't forget to unmount the partitions once your'de done.

How to set root password on ReadyNAS

Recently I had forgotten my ReadyNAS password.  Even worse, I couldn't login at all due reckless upgrade I did on the box.  I was able to undo the upgrade by letting the box recopy the Linux from its firmware to the drive (see ReadyNAS forum/documentation on how to make the ReadyNAS box recopy the firmware), but still I forgot what my root password was.

Various steps I had tried as I found on the Internet as well as on the ReadyNAS website, but none of them work. Finally, I had an idea to just access the drive directly thru SATA-to-USB cable and reset the password manually.

Basically what I did was to set the root password stored in the file /etc/passwd (fortunately the authententication is still the old-fashioned one, where the MD5 encrypted password stored directly in the file instead in shadow file).

You might ask, "How the hell I access the drive?".  Well, first you need remove the drive from the ReadyNAS bay (make sure it is turned off!!) then  attach the SATA-to-USB cable to the drive.  Connect the usb end to our PC.

We cannot mount directly to the drive, because some other issues.  To mount, see my previous post ("How to mount disk used by ReadyNAS").  Once it is  mounted (just mount the ext3 partition [first partition], no need to mount the LVM), we can now modify the file /etc/passwd.

First, save the following script (thanks to somebody who posted it on the Internet), say, as /home/<yourloginname>/bin/setpasswd:


#!/usr/bin/perl
################################################################################
# Generate an MD5 hash for a string.
# Created to allow me to set a blank Linux password. Required this to create
# multiple VsFTP accounts with anonymous style credientials.
#
# If all you want is the MD5 Hash for NULL (blank password) here's one...
# $1$VNMbpxGH$sew7cnwH9ixU.x27UbFNn.
#
# Advice: If replacing a Linux password with a blank string, ensure you give 
# the user a shell of /sbin/nologin as you wouldn't want them to login!
################################################################################
# Load dependancies...
# perl -MCPAN -e 'install Crypt::PasswdMD5'
################################################################################

use strict;
use Crypt::PasswdMD5 qw(unix_md5_crypt);
my @salt = ( '.', '/', 0 .. 9, 'A' .. 'Z', 'a' .. 'z' );
my %encrypted;


sub abort {
print "ABORT: $_[0]\n";
exit 1
}


sub gensalt { #------------------------------------------------------------
# uses global @salt to construct salt string of requested length
my $count = shift;

my $salt;
for (1..$count) {
$salt .= (@salt)[rand @salt];
}

return $salt;
} # end gensalt


sub get_encryptedpw { #--------------------------------------------------
my $unencrypted="$_[0]";

# generate traditional (weak!) DES password, and more modern md5
$encrypted{des} = crypt( $unencrypted, gensalt(2) );
$encrypted{md5} = unix_md5_crypt( $unencrypted, gensalt(8) );

return %encrypted;
}

################################################################################
print "Enter password string to encrypt (can be blank) : ";
my $password = <STDIN>;
chomp $password;

get_encryptedpw($password);

print "Plaintext \"$password\" = MD5 Hash: $encrypted{md5}\n";
print "\nReplace the /etc/shadow password string with the above to force pass change\n";


(Don't forget to make it executable by doing "chmod +x ./setpasswd)
Run the script.  It will ask you to enter a password.  An example of the output (with blank password):


$ setpasswd
Enter password string to encrypt (can be blank) : 
Plaintext "" = MD5 Hash: $1$udf2EDLY$a/cLQQ4h25rwZQc9VKmG6/

Replace the /etc/shadow password string with the above to force pass change

Copy the portion after the string "MD5 Hash: " above and paste it in the <READYNAS MOUNTPOINT>/etc/passwd.  To be precise, it should be pasted in line where "root:...". Paste it right after "root:", and let the rest of the existing text still intact.

Save the file, unmount (just use the regular umount for this one), reinsert the drive into the ReadyNAS bay and turn it on.  Once it is running, try to SSH to the box as root and enter the new password.  It should work!